Explosive mine



Mmmmwcm Original Filed Nov. 18

, 1918 2 srmheen 1 .TREC

lua nnunbmuun uw EXPLQSIVE DEVICES Patented Apr. 22, 1924.

UNITED STATES PATENT OFFICE.

JOI-IN J'. DUFFIE, 0F BERKELEY, CALIFORNIA, ASSIGNOR T0 THE GOVERNMENT OF THE UNITED STATES.

EXPLOSIVE MINE.

Application filed November 18, 1918, Serial No. 263,082.

To all whom t may concern.'

Be it known that I, JOHN J. DUFFIE, a citizen of the United States, residing at Berkeley, California, have invented new and useful Improvements in Explosive Mines, of which the following is a specification.

This invention concerns a device adapted to be used in connection with submarine mines Jfor the protection of harbors, shipping, etc., which device is adapted to be actuated to fire the mine onthegcontinjjedm presence in the immediate vicinitywtlereof of amsiiblnarine, surface vessel, or the like.

@ne of the objects of this invention is to provide a mechanism for mines which will elfect the explosion of the mine on the continued presence within the zone ot effective ness of said mine of a submarine, surface vessel, or the like. Another object of this invention is to provide a mechanism for controlling the firing of a mine which will always require for its actuation...thepresence, for a defini/te interval of timewyvithinvi'ts zone of eii'ectiveHess-oflibject sought to be destroyed. Another object is to provide a mechanically operating time con trolled firing mechanism for a mine.

Still further objects of this invention will be brought out and made clear by reference to the accompanying specification in which T have described one form of embodiment of my invention, it being understood that the device hereinafter described is merely exemplary of the broad principle herein involved and is susceptible of other and various modifications which are comprehended within the sco-pe of the invention.

This invention is an improvement over the invention disclosed in my copending application No. 215,970, filed February S, 1918, for explosive mines.

Referring now to the drawings in which like characters of reference designate like parts,

Figure 1 is a diagrammatic view showing the general arrangements of the various elements.

Figure 2 is a top plan view, part in section, of the timing mechanism for closing the firing circuit, while,

Renewed January 5, 1923.

posed in the side or near the top of the mine case A, which transmitter 2 includes the usual carbon container or chamber 2. A wire or conductor 3 is connected to one of the electrodes of the microphone and this leads to one end of a primary winding 1 of an induction coil 5, a wire or conductor 6 leading from theother side of the primary winding 4 and being connected to the diaphragm 1, a battery? being included in the circuit thus formed. Secondary windings 8 of the induction coil 5 pass thence around the poles ot an electromagnet 9, which magnet, when energized, is adapted to attract the neighboring diaphragm 10 supported in a suitable casing. A post 11, carried by the diaphragm 10, contacts normally with a contact provided on one end oi a lever 13 pivoted at 14. A spring 15. tensioned by means of the spindle 16 and the thumb wheel 17, acts normally to maintain contact between the post 11 and the lever 13.

The diaphragm 10, post 11` and lever arm 13, form partlof an electric circuit, including a battery 18 and the wire 20, connected at one end to the diaphragm 11D, and passing thence around the poles of an electromagnet 19, to insulated supporting post 21., carrying the lever arm 13, and being finally connected to the opposite side of the battery 18. An adjustable stop 22 is provided. adapted to cooperate with pivoted arm 23, carrying an armature 21 disposed adjacent the pole of the electromagnet 19, which armature is arranged to normally be attracted by said magnet. The arm 23 carries a contact 25, which, by means of weak spring 26, is adapted to be held in contact with adjustable stop 27 when magnet 19 is cle-energized, and thus close the circuit including wires 28 and 29.

So far I have described features of construction which are disclosed in my cepending application above referred to and the operation of this part of the device is brief-ly as follows:

On the approach through the water of a submarine, a surface vessel, or other `spunti,giyingk body, sound waves will be re- Figures 3, 4, and 5, are detailed views of Mceived by themdiaphragm 1 and when of features of construction of that part of the device shown in Figure 2.

Referring now to`Figure 1, the diaphragm 1 of a microtelephonic transmitter 2 is dissulicient intensity will produce a vibration of said diaphragm. This will alternately compress and then relieve of pressure the carbon granules in the microphone 2 and in a well known manner will produce variations in the strength of the current passing through the primary winding 4 of the induction coil 5. These variations in the strength of the current in the primary windings 4 will produce an induced current in the secondary windings 8, which current will energize the electromagnet 9, the poles of which thereupon attract the diaphragm 10. The current induced in the electromagnet 9 being an alternating current, the post 11 carried by the diaphragm 10 will be set in vibration and as the lever 13 has a certain momentum, the contact of lever 13 with post 11 will be interrupted and for the most part broken, thus breaking the normally closed circuit including battery 18 and conductor 20. The electromagnet 19, which has heretofore been actuated by the battery 18, no longer possesses sufficient magnetic strength to attract and hold the armature 24 of the arm 23 but the spring 26, acting on said arm 23, may now overcome the weak effect of the magnet 19 and hold the contact 25 against the adjustable contact 27.

The wires 28 and29 before described form part of an electrical circuit including a batteI'y 30 and a variable resistance 31, the wire 28 passing around the poles of an electro magnet 32 before leading tol the resistance 3l. The magnet 32 is adapted when energized to effect the movement of a lever arm, later to be described, to bring into action the mechanically operated timed firing mechanism, designated broadly as 33, which is shown more in detail in Figures 2, 3, 4, and 5. Thus the magnet 32, the lever arm above mentioned, and the meansk heretofore described for effecting the energization of the magnet, constitute a sound actuated means which, governed by the micro-telephonic transmitter 2, or other sound responsive means, forms one unit of my device.

Referring now to Sheet 2 of the drawing, a helical spring 34 is s ecured at one end to a large gear 35 and is attached at its other end to a stationary part of the framework, formed by front and rear plates 36 and 37 respectively, connected at different points by suitable spacing members so as to provide bea-rings for various gear carrying shafts, including shaft 38 on which t-he gear 35 is mounted.

The gear 35 meshes with a pinion 39 secured to a shaft 40 which carried the gear 41. This gear 41 meshes with the pinion 42, mounted on the shaft 43, and carrying the gear 44. In a similar way gear 44 meshes with pinion 45 on shaft 46 carrying gears 47 and 48. The gear 48 meshes with a contact carrying gear 49, while the gear 47 meshes with a pinion 50, attached to a shaft 51, carrying the escape-wheel 52. This escape wheel cooperates with an escapement 53, pivot-ed at 54, and provided with a fork end 55, engaging a pin 56, carried by the balance wheel 57, mounted on a shaft 58. This balance wheel 57 is of usual construction and is operated in the usual manner by helical spring 59, connected at its inner end to the wheel, and secured at its outer end to some stationary part of the frame.

To the shaft 58 is secured a cam-shaped retaining member 60. This retaining member 60 is adapted to cooperate with a hookshaped end 61 of a pivoted lever 62, fulcrumed about shaft 62 the opposite end 63 of which is forked-shaped to provide a mounting for the shaft 64, carrying the gear An arm 65 projects from one side of this lever and has secured thereto one end of a retracting spring 66,. the other end of which is secured at. 67 to the rear plate 37 of the frame. So long as the mine is not affected by any sound giving body to set up vibrations in the diaphragm 1, the spring 65 will tend to hold the lever 61 in that position that the hook-shaped end 61 thereof will enga-ge the cam-shaped member 60 to hold the balance wheel 57 o center, that is, to hold the balance wheel in such a position that Were the wheel free to move, the spring 59 would tend to move it in one direction or the other, At this time the contact carrying gear 49 will be held out of engagement with the gear 48, so that the gear train before traced is normally disconnected. Adjustable stops 68 and 69 regulate the extent of movement of the arm 65, and an armature 7() carried by the arm 65 is disposed adjacent one end of the poles of the electro magnet 32.

Referring now to Figure 5, a conta-ct pin 71 is secured to the under side of gear 49, and is adapted to contact with a cooperating L-shaped contact member 72,' secured to arm 73, pivotally mounted on a bolt 74, which is insulated from the rear frame 37 by means. of bushings 75 and 76. of nonconducting material. This arm 73 carries a pointer 77 and is mounted above a graduated dial 78, the pointer 77 cooperating with the graduations on the dial so that the position of the arm 73 may be adjusted with relation to the graduations on the dial.

A small spring member 79, (see Figure 2), is secured to the lower fork of the end 63 of lever 62 in the path of pin 71 and a spring is attached at its inner end to the gear 49 and at its outer end to some stationary part of the framework so as to normally hold the pin 71 in contact with the spring member 79 when the gear 49 is out of mesh with the gear 48. The spring 79 provides the necessary amount of resiliency to protect the pin 71 from being bent or fractured when spring 80 moves gear to carry the pin 71 back to its initial position after gear 49 has been moved around and 22121.08 IVE DEVICES again released, in a manner later to be described.

To the under side ot' lever 65 a pawi 81 is pivoted, (see Figure 4,), which, by means of the spring 82, is normally held in engagement with the ratchet wheel 83 controlled by the spring 84, the purpose of which will be hereinafter explained.

Referring now particularly to Figures 1 and 5, it can be seen that the conductor 85 forms part of a shunt circuit leading from the wire 28 and connecting to the rear plate 37 of the frame, so that a tiring circuit 85', including conductor 85, is grounded on the trame. By this means, the pin 71 is connected to one side of the firing circuit 85 and a conductor 86, having electrical connection with the bolt 74, provides a means for connecting the contact member 72 to the tiring circuit. which is thus closed when the pin 71 and the member 72 are in co-ntact. The conductor 86 leads to a heating coil 87 or other means for detonating the priming charge in the chamber 88, and conductor 89 leads from the other side of this heating' coil or detonating means to the circuit including battery 30.

I have now described the structure of my apparatus and the operation ot the improved time controlled tiring means will be understood by the following brief description ot the operation: In a manner previously described, the circuit including wires 28 and 29 and battery 30 has been closed so that a current Hows through the electromagnet 32. This is caused, as previously described, by oscillations and vibrations of the diaphragm 1 caused by the presence in the vicinity of the mine ot a sound emitting body. The spring` 66, acting on the arm 65, has heretofore held the hook-end 61 of the lever 62 in engagement with the cam-shaped member 60, and the gear 49 carried by the forked end 63 of the lever 62 has thus been held out of engagement with the gear 48. This engagement of the hook end 61 with the cam-shaped member prevents the oscillation of the balance wheel 57. so that power from the spring 34 cannot be transmitted by way of the gear 35 and the intermediate gear train to eiect any movement of the gears.

However, the electro-magnet 32 now being excited, acts on the armature 70 ot the arm to pull the hook end 61 of the lever 62 out of its engagement with the camshaped member 60, thus releasing the balance wheel 57 and at the same time throwing gear 49 into engagement or register with gear 48. The spring 89 has heretofore held the gear 49 in such a position that the pin 71 is held in engagement with the spring 79. Also the lever arm 73 has been previously t, having reference to the graduations on dial 78, so that the contact 72 is removed from the pin 71 to the desired eX- tent. The balance wheel having been released, power is now transmitted from spring 34 to ac-tuate gear 85. This in turn actuates gear 41, which actuates gear 44, which in turn actuates gears 47 and 48. Gear 47 is connected in the usual way to the escapement 53, so that a step by step movement ot the gears is obtained in efect.

The gear 49, by means oi' gear 48, is thus moved and gradually, step by step, the pin 71 is brought away from its normal engagement with spring 79 toward the cooperating contact 72. The position of the contact 72 on arm 73 with relation to pin 71 on gear 49, provides a timing means and according to the position ot said arm, a greater or less time will elapse before the pin 71 engages the contact 72 to close the firing circuit 85'. The ring circuit 85 being closed, as such circuit does not include the resistance 31, the major part ot the current from the battery 30 passes through the firing circuit to raise the temperature of the heating coil 87 and explode the primer in chamber 88 to fire the mine.

The timing arrangement above described has been calculated and adjusted with regard to the probable speed of vessels, etc., the idea being that when the sound emitting vessel has reached the position where the diaphragm 1 would be set into vibration, the mine A would only be fired in case such vessel remained within the zone ot' receptivity for a certain predetermined interval of time. Thus, if a vessel or other sound emitting body should traverse the outer edge ot the circle defining the zone of receptivity ot the mine for a sound of that particular intensity the mine would not be tired. For, as the sound emitting object wouldleave the zone o'l receptivity 'before the Contact 71 had been moved around against Contact 72, the microphone 2 would no longer be affected to cause a variation in the circuit including the primary windings 4 and thus a current would no longer be induced in the circuit including secondary windings 8 to interrupt the normally closed circuit including battery 18 and wires 20. Thus the electromagnet 19 would overcome the weak ett'ect of spring 26 and would draw armature 24 of arm 23 into engagement with the stop 22 and out of engagement with the stop 27 so that current would no longer be sent into the circuit including wires 28 and 29. llVhen current ceases to flow through the circuit including wires 28 and 29., the electromagnet 32 is cle-energized, the retractile spring 66 is actuated to draw the arm 65 into contact with the stop 68, throw the gear 49 out of engagement with the gear 48, and to so place the hook-shaped end 61 of the lever 62 as to hold the cam-shaped member 60 in a position that the balance wheel 57 is off center. The effect of paWl 83 and ratchet 84: is to slow up this return'- ing movement of arm 65, so that slight variations in current strength passing around the poles of the electro-magnet 3:?, will not be sufiicient to enable spring 66 to withdraw arm 65 before the current is again built up.

However, should the sound emitting body remain within the zone of receptivity of the diaphragm l and continue to set up vibrations affecting the diaphragm l for a predetermined period of time, the contact 71 will be finally moved around against the contact 72 and the firing circ-uit 85 thus closed. The interval of time elapsing between the throwing into operation of the timing mechanism and the final firing of the mine is calculated and adjusted so that at the time the mine is fired, the vessel or other sound emitting object should have approached to within the Zone of greatest effectiveness of' the mine.

It is to be understood that the mine with which this device is used is preferably to form part of a mine field in which the Zones of receptivity of the various mines just meet 0r slightly overlap.

Having t-hus described I claim is:

l. In combination in a mine, an explosive charge; sound controlled means; an adjustably timed firing mechanism, including a gear train, operable by said sound controlled means to control the firing of said mine.

2. In combination in a mine, an explosive charge; adj ustably timed firing means therefor; sound controlled means; and a mechanically operating means, set in motion by said sound controlled means, to thereafter effect the actuation of said firing means after a predetermined time interval-according to the adjustment thereof.

8. In an explosive mine, in combination, sound responsive means; a normally locked self actuated gear train; a gear driven by said train but normally out of' mesh therewith for controlling the firing of the mine; an arm, carrying said gear and locking said gear train; and means made effectivev by said sound responsive means for moving said arm to unlock said gear train and throw said gear into mesh.

4. In a mine, an explosive charge; discharging means therefor; sound controlled my invention, what were'.

means; and a timing mechanism between the discharging means and sound controlled means and including a timing element and mechanical means for enga-ging said element; and means for normally maintaining said timing element out of engagement with said mechanical means.

5. In a. firing device for explosive mines, in combination, a Aspring actuated gear train; a gear driven thereby, controlling the firing of said mine; a normally locked escapement for controlling said gear train; and sound actuated means for releasing said escapement.

(S. In a firing device for explosive mines, in combination, an adjustable arm; a contact member on said arm; a firing gear; a contact member on said firing gear; a firing circuit closed through said contact members; and sound actuated means for actuating said gear to gradually bring said contacts into meeting.

7. A firing device for mines, comprising self-actuating means; a timing element normally disconnected from said means; means associated with said timing element for normally maintaining said first means inoperative, and means for simultaneously placing said timing element in cooperative relation with said first mentioned means and releasing said first mentioned means.

8. A firing device for explosive mines, comprising a timing element; actuating means for said element; means for normally maintaining said first means inoperative.; means for maintaining said timing element out of cooperative relation with said actuating means; and means whereby said timing element and actuating means are thrown into operative relation and said actuating means is rendered operative.

9. A. firing device for explosive mines, having a normally locked mechanically operated means; a timing element normally disconnected from said means; means for returning and maintaining said timing element in initial position when disconnected from said operating means; and sound controlled means for connecting the timing element and mechanically operated means and releasing said operated means.

Signed at Washington, District of Columbia, this 4th day of October, 1918.

JOHN J. DUFFIE. 

